The installation of an oil pan heater on an oil pan is known. However the general practice is to drain the oil from the oil pan, remove the oil pan from the engine block, and then drill a hole in the engine oil pan, thread the hole or weld a threaded insert to the hole with the threaded hole or threaded insert being sized to receive a oil pan heater. Then the interior of the oil pan had to be thoroughly cleaned so that there would be no debris that would contaminate the oil that would be in the oil pan when it was mounted on the engine block. This procedure took several hours and generally required the vehicle to be tied up for an entire day. The removal of the oil pan was necessary to prevent metal particles from the drilling to remain in the oil pan. Such particles would contaminate the oil and cause extensive damage to the engine. Therefor there is a need for the present invention which allows an oil heater to be mounted on an oil pan while the oil pan is pan is mounted on the engine block and which procedure will not contaminate the oil which collects and is maintained in the oil pan.